William litchfield



(No Model.) p

W. LITCHPIELD.

TENT OFFICE.

WILLIAM LITOHFIELD, OF LONDON, ENGLAND.

TYPE.

l SPECIFICATION forming part `of Letters Patent No. 598,524, datedFebruary 8, 1898.

Application filed September 3,1897. Serial No. 65(7),528. (No model.)

To @ZZ whom t may concern:

Be it known that I, WILLIAM LiTcHEIELD,

`a subject of the Queen of Great Britain, re-

siding at 26 Lewisham Park, London, in the county of Kent, England, haveinventedcertain new and useful Type, of which the following is aspecification.

In type-writers as at present constructed numerous linger-keys arerequired, one for each character employed, whether it be a capitalletter, a small letter, a cipher, a shorthand sign, a punctuation, orthe like, or if one finger-key be made to serve for two or more separatetype the mechanism is complicated thereby.

According to my invention the number of finger-keys required in atype-writer is reduced by the employment of type which print differentcharacters when the nger-key is struck with dierent degrees of force.For this purpose the face of the type is made dupleX-that is to say, ithas printing surfaces in dierent planes. Thus, to take the simplestillustration, the same type may be employed to print a comma and `asemicolon. In this case the comma will stand somewhat higher on the typethan the dot stands. Consequently when the key is lightly struck thecomma alone prints, but when` the' key is struck with more force the dotalso produces its impression. bet is suitably designed, a greatreduction may be made in the number of finger-keys Without in any waycomplicating the machine. The type of hand-stamps may similarly be madewith duplex printing-faces.

The drawings illustrate the application of the invention to atype-writer special system of shorthand.

Figure 1 is atable, the iirst column of which producing a In this way,where the alphashows the symbols produced when each of the thirty keysis struck lightly and the third column the symbols produced when thesame keysare struck heavily. The second and fourth columns give theletter or combination corresponding to each symbol. Figs. 2, 4, and 6are enlarged plan views of the type producing th and thr,? t and d, andtr and dr, respectively. Figs. 3, 5, and 7 are sections on the lines 38, 5 5, and 7 7 of Figs. 2, 4, and 6, respectively.

As shown, the symbols in column 3 of Fig.

l differ from those in column one either by the addition of a line, bythe thickening of a line, or by both. Fig. 2 is an example of the first,and Figs. 4 and 6 ofthe second, method. The addition of a line isproduced when the type has surfaces c and 6Figs. 2 and 8, at differentlevels. The higher surface a is operative whether the key be strucklightly or heavily,

while the surface. b is only operative in the latter case. A thickeningof the line is produced when the projection c on the type, Figs. A to 7,whose top is the surface a, is conical, so that the operative part isbroader when the key is struck heavily than when struck lightly. Bysimilar means three symbols may be produced by the same type; but thisis rarely convenient.

What I claim isi Type having duplex printing-faces namely an upper facewhich alone prints when the type is lightly impressed and a lower facewhich produces an impression in conjunction with that of the upper facewhen the type is more heavily printed.

WILLIAM LITOHFIELD. Witnesses:

GERALD F. BIRD, CHARLES HALE.

